Industrial microbiology involves the large-scale production of microorganisms or their products for commercial use. Microorganisms used must grow rapidly, produce the desired product efficiently, and be genetically stable. Appropriate growth media are required to support microbial growth while preventing toxic byproduct formation. Common industrial media ingredients include corn steep liquor, molasses, and sulfite liquor which provide carbohydrates, nitrogen, minerals and other nutrients. Microbial products can arise from primary metabolism during active growth or secondary metabolism in response to nutrient limitation. Screening of microbial isolates aims to find strains with desirable properties for industrial use, while further strain improvement works to enhance productivity, substrate utilization, and other economically beneficial traits.

1. Industrial Microbiology
Prepared by Mesfin Angaw

2.  Industrial microbiology is study of the large-scale
and profit motivated production of microorganisms or
their products for direct use, or as inputs in the
manufacture of other goods.
 Example
 Yeasts may be produced for direct consumption as food for
humans or as animal feed, or for use in bread-making;
 Their product, ethanol, may also be consumed in the form of
alcoholic beverages, or used in the manufacture of
perfumes, pharmaceuticals, etc.
What is Industrial Microbiology?

3. Requirements for industrially useful
microorganisms
 To be used in industrial microbiology
microorganism must be
◦ Grow in simple media: preferably not require
growth factors
◦ Grow vigorously and rapidly
◦ Produce the desired product in short time possible
◦ Its end products should not include toxic and other
undesirable materials
◦ The organism should have a reasonable genetic,
and hence physiological stability.
◦ The organism should lend itself to a suitable
method of product harvest at the end of the
fermentation.

4. ◦ Wherever possible, organisms which have
physiological requirements which protect them
against competition from contaminants should be
used.
◦ The organism should be reasonably resistant to
predators
◦ the organism should not be too highly demanding of
oxygen
◦ organism should be easily amenable to genetic
manipulation to enable the establishment of strains
with more acceptable properties.

5. Media Used in Industrial Microbiology
 Use of appropriate growth medium is important to
◦ Allow to harness the organism’s full industrial potentials.
◦ Prevent formation of toxic products.
 The basic nutrient requirements of Industrial media
◦ All microbiological media must satisfy the needs of the organism
in terms of
 carbon, nitrogen, minerals, growth factors, and Water
◦ In addition they must not contain materials which are inhibitory
to growth.

6. Media Used in Industrial Microbiology
 Media formulation
Under laboratory conditions
Purified chemicals are used since volume is
limited to a few litters
At industrial scale
Made with unpurified raw materials.

7. Criteria for the choice of raw materials used in
industrial media
◦ In deciding the raw materials to be used in the production
of a given products using designated microorganism the
following factors should be taken into account.
 Media cost must not be above the selling price.
 The raw material must be readily available in order not
to halt production.
 Proximity of the user-industry to the site of production
of the raw materials is important

8. Criteria for the choice of raw materials used in
industrial media
 Ease of disposal of wastes resulting from the raw materials.
 The quality of the raw material in terms of its composition
must be reasonably constant.
 Media must have Adequate chemical composition.
 The raw material must contain the precursors necessary for
the synthesis of the finished product.

9. Media Used in Industrial
Microbiology
 Some raw materials used in compounding industrial media
a) Corn steep liquor
b) Pharmamedia
c) Distillers soluble
d) Soya bean meal
e) Molasses
f) Sulfite liquor
g) Other Substrates (alcohol, acetic acid, methanol, methane, and
fractions of crude petroleum)

10. Corn steep liquor
 This is a by-product of starch manufacture from maize.
 As a nutrient for most industrial organisms corn steep
liquor is considered adequate, rich in carbohydrates,
nitrogen, vitamins, and minerals.
 Highly acidic, it must be neutralized (usually with
CaCO3) before use.

11. Approximate composition of corn steep liquor (%)

12. Pharmamedia
 yellow fine powder made from cotton-seed embryo.
 It is used in the manufacture of tetracycline and some semi-
synthetic penicillin.
 Rich in protein, (56% w/v) and contains 24% carbohydrate,
5% oil, and 4% ash.
 Rich in calcium, iron, chloride, phosphorous, and sulfate.

13. Distillers soluble
 By-product of the distillation of alcohol
from fermented grain. (maize or barley)
 It is rich in nitrogen, minerals, and growth
factors.

14. Composition of maize distillers soluble

15. Soya bean meal
 The seeds are heated before being extracted for oil that is used for food,
as an antifoam in industrial fermentations, or used for the manufacture
of margarine.
 The resulting dried material, soya bean meal, has about 11% nitrogen,
and 30% carbohydrate and may be used as animal feed.
 Its nitrogen is more complex than that found in corn steep liquor
 not readily available to most microorganisms, except actinomycetes.
 It is used particularly in tetracycline and streptomycin fermentations.

16. Molasses
Average composition of beet and cane molasses

17. Sulfite Liquor
 Sulfite liquor is the aqueous effluent resulting from the sulfite
process for manufacturing cellulose or pulp from wood.
 During the sulfite process, hemicelluloses hydrolyze and
dissolve to yield the hexose sugars, glucose, mannose,
galactose, fructose and the pentose sugars, xylose, and
arabinsoe.
 Used as a medium for the growth of microorganisms after
being suitably neutralized with CaCO3 and enriched with
ammonium salts or urea, and other nutrients.

18.  It has been used for the manufacture of yeasts and
alcohol.
 Some samples do not contain enough assaimilable
carbonaceous materials for some modern fermentations.
 They are therefore often enriched with malt extract,
yeast autolysate, etc.

19. Growth factors
 Not synthesized by the organism
 Must be added to the medium.
 Function as cofactors of enzymes and may be vitamins,
nucleotides etc.
 The pure forms are usually too expensive for use in
industrial media
 Growth factors are required only in small amounts.

20. Some sources of growth factors

21. Some Potential Sources of Components of Industrial
Media
Carbohydrate Sources
(a) Cassava
(b) Sweet potato
(c) Yams
(d) Cocoyam
(e) Millets
(f) Rice
(g) Sorghum
Protein Sources
(a) Peanut (groundnut) meal
(b) Blood meal
(c) Fish Meal

22. The Use Of Plant Waste
Materials In
Industrial Microbiology Media:
Saccharification Of
Polysaccharides

23.  Not only plentiful but that in contrast with petroleum, a major
source of chemicals, they are also renewable.
 Contain large amounts of polysaccharides which are not
immediately utilizable by industrial microorganisms
 Need to be hydrolyzed or saccharified to provide the more
available sugars.
 Thereafter the sugars may be fermented to ethyl alcohol for
use as a chemical feed stock.
 The plant polysaccharides include starch, cellulose and
hemicelluloses.

24. Metabolic Pathways for Synthesis of Industrial
Microbiology Products
 Metabolism is a series of chemical reactions involved in
converting a chemical in the organism into a final product.
◦ Anabolism – reactions lead to the formation of a more complex
substance
◦ Catabolism - reactions lead to less complex compounds
 The compounds involved in a metabolic pathway are called
intermediates and the final product is known as the end-
product

25. Industrial Microbiological Products As
Primary And Secondary Metabolites
 Products of industrial microorganisms may be
divided into two broad groups,
◦ Those which result from primary metabolism
and
◦ others which derive from secondary
metabolism.

26. Industrial Microbiological Products As
Primary And Secondary Metabolites
 Primary metabolism
◦ Reactions associated with growth and the
maintenance of life.
◦ It is concerned with the release of energy, and the
synthesis of important macromolecules.
◦ When primary metabolism is stopped the organism
dies.
 Products of primary metabolism are associated with
growth
 maximum production occurs in the logarithmic phase
of growth in a batch culture.
 The products are called primary metabolites.

27. Some industrial products resulting
from primary metabolism

28.  Secondary metabolism
◦ Secondary metabolism has no apparent function in
the organism.
◦ The Products are called secondary metabolites
◦ Secondary metabolites are produced in response to
a restriction in nutrients.
◦ They are produced in the stationary phase

29. Some industrial products of microbial secondary
metabolism

30. Screening For Productive Strains And Strain
Improvements In Industrial Microbiology
◦ Strain is a genetic variant or subtype of a
microorganism.
◦ Sources of microorganism is their natural habitat
 Microbes occupy every habitat on earth.
 Highly diversified
 Adapt to specific ecological niches.
 Their geographic variation is huge.
 There are huge genetic resources for new product
discovery.

31.  Isolation of microorganisms
◦ The organism include:
 Fungi, bacteria and archaea
 Isolation methods involves :
◦ Direct isolation from soil, water etc
◦ Enrichment using selective media
◦ Purification – through repeated streaking

32.  Screening
◦ Next to enrichment and isolation is screening.
◦ The pure culture must be screened for the desired
property:
Production of specific enzymes, antibiotics etc.
 Results of screening
◦ Several isolates
◦ All isolates are the same organism but different
strains.
 Limitation of natural strains
◦ Low yield

33. Strain improvement
 The Science and technology of
manipulating and improving microbial
strains, in order to enhance their
metabolic capacities for biotechnological
applications, are referred to as strain
improvement.

34. Strain improvement
 What should we look for when we plan a strain
improvement program?
 In general profit is the major motivation
 Metabolic concentrations produced by the wild type are
too low for economical process.
 For cost effective process improved strains should be
attained.

35. Strain improvement
 Targets of strain improvement
Rapid growth
Genetic stability
Non-toxicity to humans
Large cell size, for easy removal from the culture fluid
 Ability to use cheaper substrates
Elimination of the production of compounds that may interfere
with downstream processing
Increase productivity.
To improve the use of carbon and nitrogen sources.
Reduction of cultivation cost
-lower price in nutrition.
-lower requirement for oxygen.
Production of -additional enzymes.
-compounds to inhibit contaminant
microorganisms.

36. Strain improvement
 Methods for strain improvement
◦ Selection from Naturally Occurring Variants
 naturally occurring variants which over-produce the desired
product are sought.
 It is slow, and an intolerable condition in the highly competitive
world of modern industry.
 Strain improvement is therefore mostly achieved by other
means described below.
◦ Manipulation of the Genome of Industrial Organisms
1. Method not involving foreign DNA- mutagenesis
2. Methods involving foreign DNA- recombination

37. Method not involving foreign DNA
Conventional Mutation
 A mutation is a change in the sequence of the bases in
DNA.
 Mutations occur spontaneously at a low rate in a
population of microorganisms.
 It is this low rate of mutations which is partly
responsible for the variation found in natural
populations.
 An increased rate can however be induced by

38. Methods involving foreign DNA
-Recombination
 Method involving Foreign DNA (recombination)
◦ Transduction
◦ Conjugation
◦ Transformation
◦ Parasexual recombination
◦ Protoplast fusion
◦ Site-directed mutation
◦ Genetic engineering

39. Preservations of microorganisms
 Once a microorganism has been selected or created it
must be preserved in its original form for further use.
 The principles involved in preserving microorganisms
are:
a) reduction in the temperature of growth of the organism
b) dehydration or desiccation of the medium of growth
c) limitation of nutrients available to the organism.
 All three principles lead to a reduction in the organisms
metabolism.
 There are various preservation methods.

40. Preservations of microorganisms
Method of
preservation
Comments
Periodic transfer Variables of periodic transfer to new media include
transfer frequency, medium used, and holding
temperature; this can lead to increased mutation rates
and production of variants
Mineral oil slant A stock culture is grown on a slant and covered with
sterilized mineral oil; the slant can be stored at
refrigerator temperature
Preservation on
paper
A drop of broth containing spores are placed on the
sterile filter paper and dried. Used for spore-forming
microorganism
Lyophilization Water is removed by sublimation, in the presence of a
cryoprotective agent; sealing in an ampule can lead to
long-term viability, with 30 years having been reported
Preservation in
liquid nitrogen
Liquid nitrogen at -196°C is used, and cultures of
fastidious microorganisms have been preserved for
more than 15 years

41. Fomenters and fermentation
 A fermentor (or fermenter) is a vessel for the
growth of microorganisms which, while not
permitting contamination, enables the provision of
conditions necessary for the maximal production of
the desired products.
 In the chemical industry, vessels in which reactions
take place are called reactors.
 Fermentors are therefore also known as
bioreactors.

42. Structure of a Typical Fermentor

43. Fermentation
 Industrial fermentation is the large scale cultivation of
microbes to produce a commercially valuable products.
Types of fermentation
 Continuous fermentation
◦ nutrients are continuously added, and products are also continuously
removed.
 Fed-batch fermentation
◦ products are harvested, the fermentor cleaned up and recharged for
another round of fermentation.
 Batch fermentation
◦ Growth of microorganisms inoculated in a closed vessel with a single
batch of medium. Nutrients supply are not renewed nor wastes are
removed.

44. The upstream and downstream process
 Upstream
◦ Components of the production system that occur
prior to the fermentation.
◦ Includes the cleaning, media formation, sterilization
of media and vessels addition of media and
organism to vessels.
 Downstream
◦ Components of the production system that occur
after the fermentation
◦ It includes harvesting and purifications of the
products and waste disposals.

45. Food flavorings, food supplements and vitamins
 Microbes produce metabolic byproducts that improve
texture, flavor or nutrition.
 Flavorings made by microbes include
◦ Cinnamic acid – Escherichia coli, Saccharomyces
cerevisiae, Pseudomonas putida
◦ Diacetyl –lactococcus
 Vitamins
◦ Vitamins are used as food supplements for human food and
animal feeds.
◦ Most are produced commercially by chemical synthesis
◦ Few are too complicated to be synthesized inexpensively but can
be made microorganisms.

46. Food flavorings, food supplements and
vitamins
 Vitamins
◦ Due to their complex nature, two are microbial produced.
◦ Vitamin B12 - Propionibacterium and pseudomonas are main
commercial producers
◦ Riboflavin - Ashbya gossypii produce huge amount of this
vitamins.
 Amino acid
◦ Glutamic acid is used as flavor enhancer and commonly
produced by Corynebacterium glutamicum.
◦ Lysine is essential amino acid for humans and certain animals
and it is produced by Brevibacterium flavum.

47. Productions of Beer

48. Productions of Beer
 Beer is an alcoholic beverage produced by fermentation.
 Most beer is flavoured with hops, which add bitterness and
act as a natural preservative.
 The word beer derives from the Latin word
◦ Bibere meaning to drink.
 The process of producing beer is known as brewing.
 Beer brewing from barley was practiced by the ancient
Egyptians as far back as 4,000 years ago.
 But investigations suggest Egyptians learnt the art from the
peoples of the Tigris and Euphrates where man’s
civilization is said to have originated.

49. Ingredients of Beer
◦ Malt – Barley, Sorghum .
◦ Yeast – selected strain
◦ Adjuncts – any starchy materials to provide extra sugar
◦ Hop – flower of the hop plant, Humulus lupulus
◦ Water – presence of Calcium and bicarbonate ions are most important.

50. Beer production process
◦ Beer production process involves the following main step
Malting
 Germination of grain under controlled conditions.
 The purpose of malting is to develop amylases and
proteases in the grain.
 Have three stages
 Stepping – addition of water to moist the grain
 Germination
 Kilning- heating the malt in an oven to halt seedling development.

51. Beer production process
Wort production involves
• Milling – malt is cleaned and milled.
• Mashing – the ground malt and adjuncts are mixed at optimum
temperature for the amylase and protease enzyme derived from the
malt. The purpose of mashing is to extract as much as possible the
soluble portion of the malt and to enzymatically hydrolyze insoluble
portions of the malt and adjuncts.
• At the end of mashing husks and other insoluble materials are
removed.
• The aqueous solution resulting from mashing I known as wort.
• Wort boiling and hop addition
• The wort is boiled for 1-1½ hours, and Hops are also added, some
before and some at the end of the boiling.

52. Beer production process
The purpose of boiling is as follows.
 To concentrate the wort, which loses 5-8% of its volume by evaporation
during the boiling
 To sterilize the wort to reduce its microbial load before its introduction
into the fermentor.
 To inactivate any enzymes so that no change occurs in the composition
of the wort.
 To extract soluble materials from the hops, which not only aid in protein
removal but also in introducing the bitterness of hops.
 To develop color in the beer; some of the color in beer comes from
malting but the bulk develops during wort boiling.
 Removal of volatile compounds: volatile compounds such as fatty acids
which could lead to rancidity in the beer are removed.

53. Beer production process
Fermentation
◦ The cooled wort is pumped into fermentation tanks by gravity
◦ Yeast is inoculated at a rate of 7-15 x 106 yeast cells/ml.
◦ Top fermentation
 S. cervisiae is used and pitched at a temperature of 15-16°C and raised to
20°C over a period of about three days.
 Fermentation takes about six days,
 Yeasts float to the top during this period
◦ Bottom fermentation
 S. uvarum is used and inoculated at 6-10°C and is allowed to rise to 10-12°C.
 After fermentation it is stored in cellars for clarification and maturation.
 After four to five days as the yeasts begin to settle.

54. Beer production process
Packaging
 The beer is transferred to pressure tanks.
 It is distributed to cans, bottles and other containers.
 Beer is not allowed to contact with oxygen and to lose CO2,
 Bottles are thoroughly washed with hot water and sodium
hydroxide before being filled.
 Beer is bottled under a counter pressure of CO2.
 The filled and crowned bottles are passed through a pasteurizer,
set to heat the bottles at 60°C for half hour.

55. Production of wine and spirits
Wine
 Wine is by common usage defined as a product of the
“normal alcoholic fermentation of the juice of ripe grapes.
 However, any fruit with a good proportion of sugar may be
used for wine production.
 Citrus
 Bananas
 Apples
 Pineapples
 Strawberries etc. may be used for wine production.

56. Processes in Wine Making
 Ripe grapes are crushed to release the juice known as ‘must.
◦ The chief sugars in grapes are glucose and fructose
◦ Grape juice has a pH of 3.0-4.0.
 Saccaromyces cerevisiae var, ellipsoideus is ued
 Fermentation is usually overed in three to five days.
 The wine is then transferred to wooden casks to age in a
period ranging from two years to five years.
 Then wine is packaged and distributed in casks.

57. Distilled alcoholic beverages (spirits)
 The distilled alcoholic or spirit beverages are beverages
whose alcohol contents are increased by distillation.
 It is produced by extension of beer production process.
 The fermented liquid is boiled and the volatile
components are condensed to yield a product higher in
alcohol contents.
 The distilled alcoholic beverage or spirit beverage can
be prepared from
 Grain – whisky , vodka, gin
 Grape – brandy

58. Production of Organic acids
 A large number of organic acids are produced by
microorganisms.
 Organic acids of commercial interest from
microorganisms includes
 Acetic acid, Citric acid, and lactic.
 Substrates used
◦ Ethanol for acetic acid
◦ Glucose or sucrose for citric acid
◦ Lactose for lactic acid

59. Production of acetic acid
 Use
◦ Food condiment
◦ Meat and vegetable pickling and preserving
◦ Manufacture of sauce, salad dressing and tomato mustard
 Fermentation
◦ Ethanol is first produced by anaerobic fermentation of
yeast.
◦ The ethanol is aerobically oxidized to acetic acid by acid
producing bacteria of the Acetobacter.

60. Production of Citric Acid
◦ Citric acid is used in the food industry, in medicine, pharmacy
and in various other industries.
◦ It is produced by a mold Aspergillus niger using molasses.
Lactic Acid
◦ Used in baking industry , medicine, food industry as emulsifiers.
◦ Lactic acid bacteria, Lactobacillus delbruckii Lactobacillus
bulgaricus are used for the production of lactic acid.
◦ In recent times Rhizopus oryzae has been used.

61. Enzymes
 Enzymes are organic compounds which catalyze all
the chemical reactions of living things – plants,
animals and microorganisms.
 They contain mainly protein; some of them however
contain non-protein components, prosthetic groups.
 When excreted or extracted from the producing
organism they are capable of acting independently of
their source.
 It is this property of independent action which drew
early attention to their industrial use.

62. Uses Of Enzymes In Industry
 Production of nutritive sweeteners from starch
 Proteolytic enzymes in the detergent industry
 Microbial rennets
 Lactase
 The textile industry
 Pectinases for use in fruit juice and wine manufacture
 Naringinase
 Enzymes in the baking industry
 Enzymes in the alcoholic beverages industry
 Leather baiting
 Some medical uses of microbial enzymes

63. Production of Enzymes
 Fermentation for Enzyme Production
◦ Semi solid medium
◦ Submerged production
 Enzyme Extraction
 Packaging and Finishing
 Toxicity Testing and Standardization

64. Thank You & Have Cheers